This invention relates to an improved conveyor system having an upper power track for the propulsion of trolleys on a lower free track. The trolleys are used for carrying loads from one location to another and are adapted to be automatically coupled to or released from coupling members on the power track, said members include a pivotally mounted hook member, which can selectively engage one of the trolleys when the track is driven in one direction and can be pivoted out of engagement with the trolley, when the track is driven in the other direction, by means of an inclined surface riding over the trolleys on said lower free track.
Conveyor systems of this kind are used e.g. in industries for the transport of items along a manufacturing line. These conveyor systems can either be endless, so that the coupling members are driven in one direction around a circular track, or linear whereas the upper power track is reciprocally driven forwards and backwards while the coupling members pass the trolleys, without engaging these.
There is a need for using conveyor systems for transport between different levels. This is accomplished with inclined sections of the track. From economical and space related reasons it is advantageous for these inclined sections to be fairly steep.
A major problem arises in connection with these steeply inclined sections in that the engaging part of the coupling member is exposed to much more stress and can loose its grip in the trolley, e.g. from the influence of the small jolts generated when the trolley pass joints in the lower free track. A fully loaded trolley can weigh more than 200 lb and can cause considerable damage if the coupling looses its grip on the trolley in an inclined section of the conveyor system.
The reason for the present invention is therefore to produce an improved engagement between the coupling member and the trolley within inclined sections of the track. The engagement enables the coupling members to pass by the trolleys without engaging these in horizontal sections of the track, when the power driven track is reversed.